Breast Cancer Invasion and Metastasis by mPRα Through the PI3K/Akt Signaling Pathway

Pathology of breast cancer metastasis and a view of metastasis to the brain

Despite the advances in diagnosis and management of breast cancer, metastasis has been responsible for the staggering percentage of breast cancer-related death. Mortality threat can be explained mostly by the lack of proper understanding of the diversity of pathological features and underlying mechanism of breast cancer metastasis and effective targeted therapy. Breast cancer stem cells (BCSCs) are the potential source of tumor cells spread to distant organs. BCSCs targeted therapy can suppress the breast cancer progression to metastasis. Spreading of tumor cells to the bone, lung, liver, and brain occurs through a distinct non-random process; called metastasis organotropism. Recently, brain metastasis in breast cancer patients has been detected more frequently, causing a significant clinical burden. BRCA1 and BRCA2 associated breast cancers carry a remarkably higher propensity of CNS metastasis. BRCA1 and BRCA2 associated breast cancers commonly have the propensity to be the triple-negative (TN) and hormone receptors (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative molecular subtypes, respectively. Regardless of molecular subtypes, metastasis is most commonly evident at the bone. Heterogeneity is a critical pathological feature, leads to therapeutic resistance. BCSCs, biomarkers expression patterns, and mutations contribute to heterogeneity. In this paper, we discuss crucial pathological features of breast cancer metastasis, emphasizing metastasis organotropism and heterogeneity; and mechanisms of breast cancer metastasis, highlighting the pathways of metastasis to the brain. We consider that this paper reinforces future research areas and benefits the general readers, physicians, and researchers to identify potential areas to develop targeted therapies.

Expression and prognosis analysis of PAQR5 in kidney cancer

Progestin and adipoQ receptor 5 (PAQR5) affects the development of various malignancies and is specifically expressed in kidney. However, the role of PAQR5 in renal carcinoma remains unclear. We assessed the state of PAQR5 expression in kidney renal clear cell carcinoma (KIRC) by The Cancer Genome Atlas and Gene Expression Omnibus datasets. Moreover, immunohistochemistry was performed to observe the expressions of PAQR5 protein in tumor tissues. The relationships between PAQR5 expression and clinical characteristics were investigated by UALCAN. Gene Expression Profiling Interactive Analysis (GEPIA) and Kaplan–Meier plotter were used to analyze the effect of PAQR5 expression levels on overall survival and relapse-free survival (RFS). The re lationships between clinical characteristics and survival were also evaluated by univariate and multifactorial Cox regression. Gene Ontology term analysis, Kyoto Encyclopedia of Genes and Genomes analysis, and gene set enrichment analysis were performed on PAQR5 to explain the enrichment pathways and functions. Protein and protein interactions were explained by GeneMANIA and STRING. We also explored the relevance of PAQR5 to tumor immune cell infiltration and immunomodulatory molecules by TIMER and GEPIA. Finally, we explored the correlation of PAQR5 with the pathway proteins STATs, HIF-1α, and mTOR using the GSE40435 dataset. PAQR5 expression was low in KIRC and correlated significantly with clinical characteristics including cancer stage, tumor grade, and nodal metastasis status. Low PAQR5 expression was significantly associated with poorer survival. Cox regression analysis indicated that upregulation of PAQR5 was an independent factor for a good prognosis of KIRC. PAQR5 downregulation was associated mainly with STAT3 target upregulation, tumorigenesis, and poor differentiation. PAQR5 expression also correlated positively with B cells, neutrophils, macrophages, and dendritic cells and negatively with the infiltration of FOXP3⁺ Treg cells and the immune checkpoint molecules PD-1, CTLA4, and LAG3. Moreover, PAQR5 expression in KIRC was negatively correlated with the pathway proteins STAT1/2/3/4/5A, HIF-1α, and mTOR. PAQR5 is an excellent predictor of KIRC prognosis and may be a potential molecular therapeutic target.

The Signaling Pathways Associated With Breast Cancer Bone Metastasis

Background

Breast cancer (BC) is now the leading cause of cancer in women, and bone is the primary site of distant BC metastasis. BC bone metastasis seriously affects the quality of life of patients and increases the mortality rate. However, the mechanism of BC bone metastasis is not fully understood.

Main Body

Paget’s “seed and soil” hypothesis led experts to explore the relationship between surface markers and receptors in breast tumors and various growth factors in bone. The relevant breast tumor markers serve as “seeds”, and the bone microenvironment that is suitable for the survival of the tumor serves as the “soil”. These factors interact to make up an entire system and form feedback pathways that accelerate the production of various cytokines, attracting BC cells to migrate to bone tissue, which worsens the development of BC and seriously affects the prognosis of patients. This process is a vicious cycle. At present, there are seven major signaling pathways involved in BC bone metastasis: the OPG/RANK/RANKL signaling pathway, TGF-β signaling pathway, IGF system, PI3K-AKT-mTOR signaling pathway, Wnt signaling pathway and Hippo signaling pathway. In addition, FGF-FGFR signaling pathway, androgen-AR/LSD1-target gene pathway, Notch signaling pathway, JAK-STAT signaling pathway and CaN/NFATC1 signaling pathway also seem to be associated with BC bone metastasis.

Conclusion

This review focuses on the signaling pathways related to BC bone metastasis and explores the interactions among these pathways, which will lay a solid theoretical foundation for further understanding the mechanism of BC bone metastasis and developing effective targeted therapeutic drugs.

Membrane progesterone receptor α (mPRα) enhances hypoxia-induced vascular endothelial growth factor secretion and angiogenesis in lung adenocarcinoma through STAT3 signaling

Lung cancer remains a huge challenge to public health because of its high incidence and mortality, and lung adenocarcinoma (LUAD) is the main subtype of lung cancer. Hypoxia-induced vascular endothelial growth factor (VEGF) release and angiogenesis have been regarded as critical events in LUAD carcinogenesis. In the present study, membrane progesterone receptor α (mPRα) is deregulated within LUAD tissue samples; increased mPRα contributes to a higher microvessel density (MVD) in LUAD tissues. mPRα knockdown in A549 and PC-9 cells significantly inhibited STAT3 phosphorylation, as well as HIF1α and VEGF protein levels, decreasing cancer cell migration and invasion. The in vivo xenograft model further confirmed that mPRα enhanced the aggressiveness of LUAD cells. Furthermore, mPRα knockdown significantly inhibited hypoxia-induced upregulation in HIF1α and VEGF levels, as well as LUAD cell migration and invasion. Under the hypoxic condition, conditioned medium (CM) derived from mPRα knockdown A549 cells, namely si-mPRα-CM, significantly inhibited HUVEC migration and tube formation and decreased VEGF level in the culture medium. In contrast, CM derived from mPRα-overexpressing A549 cells, namely mPRα-CM, further enhanced HUVEC migration and tube formation and increased VEGF level under hypoxia, which was partially reversed by STAT3 inhibitor Stattic. In conclusion, in LUAD cells, highly expressed mPRα enhances the activation of cAMP/JAK/STAT3 signaling and increases HIF1α-induced VEGF secretion into the tumor microenvironment, promoting HUVEC migration and tube formation under hypoxia.

Molecular Characterization of Membrane Steroid Receptors in Hormone-Sensitive Cancers

Cancer is one of the most common causes of death worldwide, and its development is a result of the complex interaction of genetic factors, environmental cues, and aging. Hormone-sensitive cancers depend on the action of one or more hormones for their development and progression. Sex steroids and corticosteroids can regulate different physiological functions, including metabolism, growth, and proliferation, through their interaction with specific nuclear receptors, that can transcriptionally regulate target genes via their genomic actions. Therefore, interference with hormones’ activities, e.g., deregulation of their production and downstream pathways or the exposition to exogenous hormone-active substances such as endocrine-disrupting chemicals (EDCs), can affect the regulation of their correlated pathways and trigger the neoplastic transformation. Although nuclear receptors account for most hormone-related biologic effects and their slow genomic responses are well-studied, less-known membrane receptors are emerging for their ability to mediate steroid hormones effects through the activation of rapid non-genomic responses also involved in the development of hormone-sensitive cancers. This review aims to collect pre-clinical and clinical data on these extranuclear receptors not only to draw attention to their emerging role in cancer development and progression but also to highlight their dual role as tumor microenvironment players and potential candidate drug targets.

Cytotoxic Effects of the Selective Ligands of Membrane Progesterone Receptors in Human Pancreatic Adenocarcinoma Cells BxPC3

Progesterone and its synthetic analogues act on cells through different types of receptors, affecting proliferation and apoptosis. These compounds exert their effect through the nuclear receptors and the insufficiently studied membrane progesterone receptors (mPRs) belonging to the progestin and adiponectin Q receptor (PAQR) family. We have identified two selective ligands of mPRs that activate only this type of progesterone receptors - 19-hydroxypregn-4-en-20-one (LS-01) and 19-hydroxy-5β-pregn-3-en-20-one (LS-02). The goal of this work is to study the effect of these compounds on proliferation and death of human pancreatic adenocarcinoma cells BxPC3 and involvement of the two kinases (p38 MAPK and JNK) in signaling pathways activated by progestins through mPRs. It was shown that progesterone and the compound LS-01 significantly (p < 0.05) inhibited the BxPC3 cell viability, with JNK serving as a mediator. The identified targets of these two steroids are the genes of the proteins Ki67, cyclin D1, PCNA, and p21. Progesterone and the compound LS-01 significantly (p < 0.05) stimulate DNA fragmentation, enhancing the cell death. The p38 mitogen-activated protein kinase (MAPK) is a key mediator of this process. The BCL2A1 protein gene was identified as a target of both steroids. The compound LS-02 significantly (p < 0.05) alters membrane permeability and changes the exposure of phosphatidylserine on the outer membrane leaflet, also enhancing the cell death. This compound acts on these processes by activating both kinases, JNK and p38 MAPK. The compound LS-02 targets the genes encoding the proteins HRK, caspase 9, and DAPK.

Lost but Not Least-Novel Insights into Progesterone Receptor Loss in Estrogen Receptor-Positive Breast Cancer

Estrogen receptor α (ERα) and progesterone receptor (PgR) are crucial prognostic and predictive biomarkers that are usually co-expressed in breast cancer (BC). However, 12-24% of BCs present ERα(+)/PgR(-) phenotype at immunohistochemical evaluation. In fact, BC may either show primary PgR(-) status (in chemonaïve tumor sample), lose PgR expression during neoadjuvant treatment, or acquire PgR(-) phenotype in local relapse or metastasis. The loss of PgR expression in ERα(+) breast cancer may signify resistance to endocrine therapy and poorer outcomes. On the other hand, ERα(+)/PgR(-) BCs may have a better response to neoadjuvant chemotherapy than double-positive tumors. Loss of PgR expression may be a result of pre-transcriptional alterations (copy number loss, mutation, epigenetic modifications), decreased transcription of the PGR gene (e.g., by microRNAs), and post-translational modifications (e.g., phosphorylation, sumoylation). Various processes involved in the down-regulation of PgR have distinct consequences on the biology of cancer cells. Occasionally, negative PgR status detected by immunohistochemical analysis is paradoxically associated with enhanced transcriptional activity of PgR that might be inhibited by antiprogestin treatment. Identification of the mechanism of PgR loss in each patient seems challenging, yet it may provide important information on the biology of the tumor and predict its responsiveness to the therapy.

The Interface of Nuclear and Membrane Steroid Signaling

Steroid hormones bind receptors in the cell nucleus and in the cell membrane. The most widely studied class of steroid hormone receptors are the nuclear receptors, named for their function as ligand-dependent transcription factors in the cell nucleus. Nuclear receptors, such as estrogen receptor alpha, can also be anchored to the plasma membrane, where they respond to steroids by activating signaling pathways independent of their function as transcription factors. Steroids can also bind integral membrane proteins, such as the G protein-coupled estrogen receptor. Membrane estrogen and progestin receptors have been cloned and characterized in vitro and influence the development and function of many organ systems. Membrane androgen receptors were cloned and characterized in vitro, but their function as androgen receptors in vivo is unresolved. We review the identity and function of membrane proteins that bind estrogens, progestins, and androgens. We discuss evidence that membrane glucocorticoid and mineralocorticoid receptors exist, and whether glucocorticoid and mineralocorticoid nuclear receptors act at the cell membrane. In many cases, integral membrane steroid receptors act independently of nuclear steroid receptors, even though they may share a ligand.

Rapamycin Antagonizes BCRP-Mediated Drug Resistance Through the PI3K/Akt/mTOR Signaling Pathway in mPRα-Positive Breast Cancer

Purpose

Overexpression of breast cancer (BCa) resistance protein (BCRP) is detected in approximately 30% of BCa cases. BCRP indicates a poor response to chemotherapy, and it has become a classic target to overcome drug-resistant tumor cells. In this study, we aimed to explore the mechanism of BCRP overexpression and a strategy to reverse this overexpression in invasive BCa.

Methods

BCRP expression in BCa tissues was determined by immunohistochemistry. GSE25066 was downloaded from the NCBI GEO database. Western blot was used to determine the expression of key molecules in vitro. Cell counting kit-8 assays were used to assess the drug response of BCa cells.

Results

Our results suggested that BCRP is an independent risk factor for BCa. We further established that upon 17α-PG binding, membrane progesterone receptor α (mPRα) promoted BCRP expression via the PI3K/Akt/mTOR signaling pathway. mPRα physically interacted with p-Akt1 S473. Moreover, rapamycin, an inhibitor of mTOR complex 1 (mTORC1), downregulated BCRP expression and enhanced the effects of particular drugs, including doxorubicin and paclitaxel.

Conclusion

BCRP is a potential biomarker of poor prognosis in BCa. BCRP expression is regulated by 17α-PG in mPRα-positive BCa cells through the PI3K/Akt/mTOR signaling pathway. Rapamycin might enhance the therapeutic effect of chemotherapy agents in mPRα-positive MDA-MB-453/BCRP cells and might be a therapeutic option for mPRα-positive invasive BCa with BCRP overexpression.

Antitumor activities of Aspiletrein A, a steroidal saponin from Aspidistra letreae, on non-small cell lung cancer cells

BACKGROUND

Lung cancer is one of the leading causes of death worldwide due to its strong proliferative and metastatic capabilities. The suppression of these aggressive behaviors is of interest in anticancer drug research and discovery. In recent years, many plants have been explored in order to discover new bioactive secondary metabolites to treat cancers or enhance treatment efficiency. Aspiletrein A (AA) is a steroidal saponin isolated from the whole endemic species Aspidistra letreae in Vietnam. Previously, elucidation of the structure of AA and screening of its cytotoxic activity against several cancer cell lines were reported. However, the antitumor activities and mechanisms of action have not yet been elucidated. In this study, we demonstrated the anti-proliferative, anti-migrative and anti-invasive effects of AA on H460, H23 and A549 human lung cancer cells.

METHODS

MTT, wound healing and Transwell invasion assays were used to evaluate the anti-proliferation, anti-migration and anti-invasion effects of AA, respectively. Moreover, the inhibitory effect of AA on the activity of protein kinase B (Akt), a central mediator of cancer properties, and apoptotic regulators in the Bcl-2 family proteins were investigated by Western blotting.

RESULTS

AA exhibits antimetastatic effects in human lung cancer cells through the inhibition of the pAkt/Akt signaling pathway, which in turn resulted in a significant inhibitory effect of AA on the migration and invasion of the examined lung cancer cells.

CONCLUSIONS

Aspiletrein A may be a potent inhibitor of protein kinase B (Akt). Hence, AA could be further explored as a potential antimetastatic lead compound.

Selective ligands of membrane progesterone receptors as a key to studying their biological functions in vitro and in vivo

Progesterone modulates many processes in the body, acting through nuclear receptors (nPR) in various organs and tissues. However, a number of effects are mediated by membrane progesterone receptors (mPRs), which are members of the progestin and adipoQ (PAQR) receptor family. These receptors are found in most tissues and immune cells. They are expressed in various cancer cells and appear to play an important role in the development of tumors. The role of mPRs in the development of insulin resistance and metabolic syndrome has also attracted attention. Since progesterone efficiently binds to both nPRs and mPRs, investigation of the functions of the mPRs both at the level of the whole body and at the cell level requires ligands that selectively interact with mPRs, but not with nPRs, with an affinity comparable with that of the natural hormone. The development of such ligands faces difficulties primarily due to the lack of data on the three-dimensional structure of the ligand-binding site of mPR. This review is the first attempt to summarize available data on the structures of compounds interacting with mPRs and analyze them in terms of the differences in binding to membrane and nuclear receptors. Based on the identified main structural fragments of molecules, which affect the efficiency of binding to mPRs and are responsible for the selectivity of interactions, we propose directions of modification of the steroid scaffold to create new selective mPRs ligands.

Classical and Non-Classical Progesterone Signaling in Breast Cancers

Much emphasis is placed on estrogen (E2) and estrogen receptor (ER) signaling as most research is focused on understanding E2 and ER’s ability to enhance proliferative signals in breast cancers. Progesterone (P4) is important for normal mammary gland development, function and menstrual control. However, P4 and its receptors (PRs) in breast cancer etiology continue to be understudied and its role in breast cancer remains controversial. The Women’s Health Initiative (WHI) clinical trial clearly demonstrated the importance of progestogens in breast cancer development. P4 has historically been associated with classical-signaling through nuclear receptors, however non-classical P4 signaling via membrane receptors has been described. Progestogens have the ability to bind to nuclear and membrane receptors and studies have demonstrated that both can promote breast cancer cell proliferation and breast tumor growth. In this review, we attempt to understand the classical and non-classical signaling role of P4 in breast cancers because both nuclear and membrane receptors could become viable therapeutic options for breast cancer patients.

Progesterone/Org inhibits lung adenocarcinoma cell growth via membrane progesterone receptor alpha

BACKGROUND

The aim of this study was to determine whether progesterone could inhibit the growth of lung adenocarcinoma cells via membrane progesterone receptor alpha (mPRα) and elucidate its potential mechanism. The relationship between mPRα expression and the survival prognosis of lung adenocarcinoma patients was studied.

METHODS

A mPRα knockdown lung adenocarcinoma cell line was constructed and treated with P4 and Org (a derivative of P4 and specific agonist of mPRα). Cell proliferation was assessed using CCK-8 and plate colony formation assays. Protein expression was detected by western blotting. A nude mouse model of lung adenocarcinoma was established to assess the antitumor effect of P4/Org in vivo.

RESULTS

We initially determined that mPRα could promote the development of lung adenocarcinoma through the following lines of evidence. High expression of mPRα both at the mRNA and protein level was significantly associated with the poor prognosis of lung adenocarcinoma patients. The downregulation of mPRα inhibited the proliferation of lung adenocarcinoma cells. We further showed that mPRα mediates the ability of P4 to inhibit the growth of lung adenocarcinoma cells through the following lines of evidence: P4/Org inhibited the proliferation of lung adenocarcinoma cells; mPRα mediated the ability of P4/Org to inhibit lung adenocarcinoma cell proliferation; mPRα mediated the ability of P4/Org to inhibit the PKA (cAMP-dependent protein kinase)/CREB (cAMP responsive element binding protein) and PKA/β-catenin signaling pathways; and P4/Org inhibited the growth of a lung adenocarcinoma tumor model in vivo.

CONCLUSIONS

In summary, the results of our study show that progesterone can inhibit lung adenocarcinoma cell growth via mPRα.

Guizhi Fuling Decoction inhibiting the PI3K and MAPK pathways in breast cancer cells revealed by HTS2 technology and systems pharmacology

As one of the classical traditional Chinese medicine (TCM) prescriptions in treating gynecological tumors, Guizhi Fuling Decoction (GFD) has been used to treat breast cancer (BRCA). Nonetheless, the potential molecular mechanism remains unclear so far. Therefore, systems pharmacology was used in combination with high throughput sequencing-based high throughput screening (HTS2) assay and bioinformatic technologies in this study to investigate the molecular mechanisms of GFD in treating BRCA. By computationally analyzing 76 active ingredients in GFD, 38 potential therapeutic targets were predicted and significantly enriched in the "pathways in cancer". Meanwhile, experimental analysis was carried out to examine changes in the expression levels of 308 genes involved in the "pathways in cancer" in BRCA cells treated by five herbs of GFD utilizing HTS2 platform, and 5 key therapeutic targets, including HRAS, EGFR, PTK2, SOS1, and ITGB1, were identified. The binding mode of active compounds to these five targets was analyzed by molecular docking and molecular dynamics simulation. It was found after integrating the computational and experimental data that, GFD possessed the anti-proliferation, pro-apoptosis, and anti-angiogenesis activities mainly through regulating the PI3K and the MAPK signaling pathways to inhibit BRCA. Besides, consistent with the TCM theory about the synergy of Cinnamomi Ramulus (Guizhi) by Cortex Moutan (Mudanpi) in GFD, both of these two herbs acted on the same targets and pathways. Taken together, the combined application of computational systems pharmacology techniques and experimental HTS2 platform provides a practical research strategy to investigate the functional and biological mechanisms of the complicated TCM prescriptions.

RRM2 elicits the metastatic potential of breast cancer cells by regulating cell invasion, migration and VEGF expression via the PI3K/AKT signaling

Breast cancer is the second leading primary cause for cancer-related mortality among women and metastasis to the brain is a disastrous event for patients with increasing incidence. A previous study confirmed the critical function of RRM2 in breast cancer cell growth. Unfortunately, the role and fundamental molecular mechanism of RRM2 in breast cancer metastasis remains elusive. In the current study, higher RRM2 expression was validated in breast cancer tissues, especially in the brain metastasis group. Simultaneously, the expression of RRM2 was increased in breast cancer cells relative to the normal breast epithelial cell line MCF-10A, concomitant with higher levels of RRM2 in the highly metastatic MDA-MB-231 cell line relative to the weakly metastatic MCF-7 cell line. Knockdown of RRM2 by small interfering-RRM2 transfection notably suppressed the malignant metastatic behavior of breast cancer cells, including invasion and migration. Simultaneously, RRM2 downregulation also restrained the transcription and release of vascular endothelial growth factor (VEGF) in breast cancer cells. Moreover, inhibition of RRM2 dampened the activation of phosphatidylinositol 3 kinase (PI3K)/protein kinase B (AKT) signaling by decreasing phosphorylated-AKT and downstream matrix metalloproteinases-2 expression. Intriguingly, reactivation of the PI3K/AKT pathway with its agonist insulin-like growth factor-1 reversed the adverse effects of RRM2 suppression on cancer cell invasion, migration and VEGF expression. Together, these findings suggest that RRM2 may act as a pro-metastatic factor to facilitate breast cancer metastasis by evoking cell invasion, migration and VEGF expression through the PI3K/AKT signaling pathway. This study may provide an attractive target for metastatic intervention in breast cancer.

Activation of membrane progesterone receptor-alpha increases proliferation, migration, and invasion of human glioblastoma cells

BACKGROUND AND AIMS

Glioblastoma is the most frequent and aggressive brain tumor due to its high capacity to migrate and invade normal brain tissue. The steroid hormone progesterone (P4) contributes to the progression of glioblastoma by promoting proliferation, migration, and cellular invasion through the activation of its intracellular receptor (PR). However, the use of PR antagonist RU486 partially blocks the effects of P4, suggesting the participation of signaling pathways such as those mediated by membrane receptors to P4 (mPRs). Therefore, this study aimed to investigate the effects of mPRα subtype activation on proliferation, migration, and invasion of human glioblastoma cells.

METHODS

We treated human glioblastoma cell lines U87 and U251 with the specific mPRα agonist Org OD 02-0, and evaluated its effects on cell number, proliferation, migration, and invasion. Additionally, we measured the phosphorylation of the kinases Src and Akt in both cell lines upon Org OD 02-0 treatment.

RESULTS

Org OD 02-0 (100 nM) augmented the number of U87 and U251 cells by increasing cell proliferation. The treatment with this agonist also increased U87 and U251 cell migration and invasion. Both proliferation and cell invasion decreased when mPRα expression was silenced. Finally, we observed that Org OD 02-0 increased the content of p-Src and p-Akt in both cell lines.

CONCLUSION

Our data suggest that P4 produces its effects in human glioblastoma progression not only by PR interaction but also through cell signaling pathways activated by mPRα.

Differential Impact of Flavonoids on Redox Modulation, Bioenergetics, and Cell Signaling in Normal and Tumor Cells: A Comprehensive Review

SIGNIFICANCE

Flavonoids can interact with multiple molecular targets to elicit their cellular effects, leading to changes in signal transduction, gene expression, and/or metabolism, which can, subsequently, affect the entire cell and organism. Immortalized cell lines, derived from tumors, are routinely employed as a surrogate for mechanistic studies, with the results extrapolated to tissues in vivo. Recent Advances: We review the activities of selected flavonoids on cultured tumor cells derived from various tissues in comparison to corresponding primary cells or tissues in vivo, mainly using quercetin and flavanols (epicatechin and (-)-epigallocatechin gallate) as exemplars. Several studies have indicated that flavonoids could retard cancer progression in vivo in animal models as well as in tumor cell models.

CRITICAL ISSUES

Extrapolation from in vitro and animal models to humans is not straightforward given both the extensive conjugation and complex microbiota-dependent metabolism of flavonoids after consumption, as well as the heterogeneous metabolism of different tumors.

FUTURE DIRECTIONS

Comparison of data from studies on primary cells or in vivo are essential not only to validate results obtained from cultured cell models, but also to highlight whether any differences may be further exploited in the clinical setting for chemoprevention. Tumor cell models can provide a useful mechanistic tool to study the effects of flavonoids, provided that the limitations of each model are understood and taken into account in interpretation of the data.

Molecular Subtypes and Prognostic Factors among Premenopausal and Postmenopausal Thai Women with Invasive Breast Cancer: 15 Years Follow-up Data

Background and Purpose: This study focused on molecular subtypes and prognostic factors for survival of preand post-menopausal breast cancer patients. Methods: A retrospective cohort study was performed on 523 patients with invasive carcinoma of the breast treated at Ubon Ratchathani Cancer Hospital,Thailand from 2002 to 2016. Patient characteristics were collected based on a systematic chart audit from medical records. Prognostic factors were performed by observe survival analysis. A Cox regression model was used to calculate hazard ratios of death, taking into account the age and menopause status, molecular subtype, stage of disease, histological grade, lymphatic and vascular invasion, resection margin, hormone receptor expression, and treatment modality. Results: The median time from the diagnosis of invasive breast cancer to the last follow-up or death was 10.2 [95% CI = 9.28-11.95] years in premenopausal women, and 7.4 [95% CI = 6.48-8.44] years in postmenopausal cases. The overall survival estimates at 5 and 10 years for younger woman of 71.2% and 51.8% respectively, appeared slightly better than the 68.3% and 40.9% for postmenopausal women [HRadj = 1.27, 95% CI =0.99-1.63]. In the multivariate analysis, 3 prognostic indicators significantly predicted a worse overall survival in premenopausal patients, triple negative subtype [HRadj = 6.03, 95% CI = 1.94-18.74], HER2-enriched status [HRadj = 4.11, 95% CI = 1.59-10.65] and stage III [HRadj = 2.73, 95% CI = 1.10-6.79]. Statistically significant increased risk of death in postmenopausal patients was noted for only chemotherapy after mastectomy [HRadj = 8.76, 95% CI = 2.88-26.61], and for a Luminal B status [HRadj = 3.55, 95% CI = 1.47-8.53]. Conclusion: Postmenopausal women with invasive breast cancer experience a significantly shorter survival than do their premenopausal counterparts. The predictors of worse overall survival were molecular subtype, stage of disease and type of treatment administered.

Exploring the molecular mechanism associated with breast cancer bone metastasis using bioinformatic analysis and microarray genetic interaction network

BACKGROUND

Bone metastases are common in advanced breast cancer patients and frequently leading to skeletal-related morbidity and deterioration in the quality of life. Although chemotherapy and hormone therapy are able to control the symptoms caused by bone destruction, the underlying molecular mechanisms for the affinity of breast cancer cells towards skeletal bones are still not completely understood.

METHODS

In this study, bioinformatic analysis was performed on patients' microarray gene expression data to explore the molecular mechanism associated with breast cancer bone metastasis. Microarray gene expression profile regarding patients with breast cancer and disseminated tumor cells was downloaded from Gene Expression Omnibus (GEO) database (NCBI, NIH). Raw data were normalized and differently expressed genes were identified by using Significance Analysis of Microarrays (SAM) methods. Protein interaction networks were expanded using String. Moreover, molecular functions, biological processes and signaling pathway enrichment analysis were performed using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG).

RESULTS

We identified 66 differentially expressed genes. After submitting the set of genes to String, genetic interaction network was expanded, which consisted of 110 nodes and 869 edges. Pathway enrichment analysis suggested that adhesion kinase, ECM-receptor interaction, calcium signaling, Wnt pathways, and PI3K/AKT signaling pathway are highly associated with breast cancer bone metastasis.

CONCLUSION

In this study, we established a microarray genetic interaction network associated with breast cancer bone metastasis. This information provides some potential molecular therapeutic targets for breast cancer initiation and progression.

Global expression profiling and pathway analysis of mouse mammary tumor reveals strain and stage specific dysregulated pathways in breast cancer progression

It is believed that the alteration of tissue microenvironment would affect cancer initiation and progression. However, little is known in terms of the underlying molecular mechanisms that would affect the initiation and progression of breast cancer. In the present study, we use two murine mammary tumor models with different speeds of tumor initiation and progression for whole genome expression profiling to reveal the involved genes and signaling pathways. The pathways regulating PI3K-Akt signaling and Ras signaling were activated in Fvb mice and promoted tumor progression. Contrastingly, the pathways regulating apoptosis and cellular senescence were activated in Fvb.B6 mice and suppressed tumor progression. We identified distinct patterns of oncogenic pathways activation at different stages of breast cancer, and uncovered five oncogenic pathways that were activated in both human and mouse breast cancers. The genes and pathways discovered in our study would be useful information for other researchers and drug development.

miR-133 involves in lung adenocarcinoma cell metastasis by targeting FLOT2

BACKGROUND

Dysregulated microRNAs (miRNAs) reported to involve into the oncogenesis and progression in various human cancers. However, the roles and mechanism of miR-133 in lung adenocarcinoma remain largely unclear.

METHODS

In this study, qPCR assay and western blot were used to detect the expression levels of miR-133, Akt and FLOT2. Luciferase reporter assay was used to identify the target role of miR-133 on FLOT2. The cell invasion and the migration capability were performed using the transwell invasion assay and wound healing assay.

RESULTS

We found that miR-133 expression levels were downregulated in human lung adenocarcinoma specimens and cell lines compared with the adjacent normal tissues and normal human bronchial epithelial cell. miR-133 significantly suppressed metastasis of lung adenocarcinoma cells in vitro. Furthermore, FLOT2 (flotillin-2) identified as a direct target of miR-133, and FLOT2 expression levels were inversely correlated with miR-133 expression levels in human lung adenocarcinoma specimens. And the restoration studies suggested FGF2 as a downstream effector of miR-133 which acted through Akt signalling pathway.

CONCLUSIONS

Our study revealed the mechanism that miR-133 suppresses lung adenocarcinoma metastasis by targeting FLOT2 via Akt signalling pathway, implicating a potential prognostic biomarker and therapeutic target for lung adenocarcinoma treatment.

A Comprehensive Model for Predicting Recurrence and Survival in Cases of Chinese Postoperative Invasive Breast Cancer

We investigated relationships between clinical pathologic data, molecular biomarkers and prognosis of invasive breast cancer based on a Chinese population. Immunohistochemistry (IHC) was used to assess the status of ER, PR, HER-2 and Ki-67, with fluorescence in situ hybridization (FISH) performed to further confirm HER-2 positivity with an equivocal result (IHC 2+). Subsequently, Kaplan-Meier univariate and multivariate COX regression analyses of ER, PR, HER-2, Ki-67, clinical features, therapeutic status and follow-up data were performed according to the establishment principle of the Nottingham prognostic index (NPI). From this study, age, tumor size, lymph node status, ER, HER-2, Ki-67 status were found to be associated with prognosis. Eventually, a prognostic model of (PI= (1.5×age) - size + (0.1×lymph node status) - (0.5×ER) + (2×HER-2) - (0.2×Ki-67)) was established with 288 randomly selected patients and verified with another 100 cases with invasive breast cancer. Pearson correlation analysis demonstrated a significant positive correlation index of 0.376 (P=0.012<0.05) between the prognostic index (PI) and actual prognosis. Remarkably, the consistency with the model predicted recurrence was 93% in the validation set. Therefore, it appears feasible to predict the prognosis of individuals with invasive breast cancer and to determine optimal therapeutic strategy with this model.

miR-24 represses metastasis of human osteosarcoma cells by targeting Ack1 via AKT/MMPs pathway

The expression levels of the protein tyrosine kinase Ack1 has been reported to be dysregulated in various cancers and involve in oncogenesis and progression. However, the expression and role of Ack1 in osteosarcoma remains unknown. In this study, we found that Ack1 were evidently upregulated in human osteosarcoma tissues and cell lines. In addition, the clinical data showed that high expression level of Ack1 is closely associated with clinical stage and positive distant metastasis, and negatively correlated with overall survival. Then, bioinformatics prediction and luciferase reporter assay indicated Ack1 as a direct target of miR-24, and Ack1 could be downregulated by miR-24 at both the mRNA and protein expression levels. Moreover, Ack1 expression levels were inversely correlated with that of miR-24 in osteosarcoma tissues. Furthermore, functional assay showed that miR-24 significantly suppressed osteosarcoma progression partially mediated by inhibiting Ack1 expression. Finally, western bolt assay revealed that miR-24 regulate AKT/MMPs pathway via Ack1 in osteosarcoma cells. In conclusion, our study demonstrated the suppression of miR-24 on osteosarcoma metastasis by targeting Ack1 via AKT/MMPs pathways, providing a novel strategy for the diagnosis and treatment of osteosarcoma patients.

Progesterone inhibits proliferation and modulates expression of proliferation-Related genes in classical progesterone receptor-negative human BxPC3 pancreatic adenocarcinoma cells

Recent studies suggest that progesterone may possess anti-tumorigenic properties. However, a growth-modulatory role of progestins in human cancer cells remains obscure. With the discovery of a new class of membrane progesterone receptors (mPRs) belonging to the progestin and adipoQ receptor gene family, it becomes important to study the effect of this hormone on proliferation of tumor cells that do not express classical nuclear progesterone receptors (nPRs). To identify a cell line expressing high levels of mPRs and lacking nPRs, we examined mRNA levels of nPRs and three forms of mPRs in sixteen human tumor cell lines of different origin. High expression of mPR mRNA has been found in pancreatic adenocarcinoma BxPC3 cells, while nPR mRNA has not been detected in these cells. Western blot analysis confirmed these findings at the protein level. We revealed specific binding of labeled progesterone in these cells with affinity constant similar to that of human mPR expressed in yeast cells. Progesterone at high concentration of 20 μM significantly reduced the mRNA levels of proliferation markers Ki67 and PCNA, as well as of cyclin D1, and increased the mRNA levels of cyclin dependent kinase inhibitors p21 and p27. Progesterone (1 μM and 20 μM) significantly inhibited proliferative activity of BxPC3 cells. These results point to anti-proliferative effects of the progesterone high concentrations on BxPC3 cells and suggest that activation of mPRs may mediate this action. Our data are a starting point for further investigations regarding the application of progesterone in pancreatic cancer.

Molecular Mechanisms and Metabolomics of Natural Polyphenols Interfering with Breast Cancer Metastasis

Metastatic cancers are the main cause of cancer-related death. In breast primary cancer, the five-year survival rate is close to 100%; however, for metastatic breast cancer, that rate drops to a mere 25%, due in part to the paucity of effective therapeutic options for treating metastases. Several in vitro and in vivo studies have indicated that consumption of natural polyphenols significantly reduces the risk of cancer metastasis. Therefore, this review summarizes the research findings involving the molecular mechanisms and metabolomics of natural polyphenols and how they may be blocking breast cancer metastasis. Most natural polyphenols are thought to impair breast cancer metastasis through downregulation of MMPs expression, interference with the VEGF signaling pathway, modulation of EMT regulator, inhibition of NF-κB and mTOR expression, and other related mechanisms. Intake of natural polyphenols has been shown to impact endogenous metabolites and complex biological metabolic pathways in vivo. Breast cancer metastasis is a complicated process in which each step is modulated by a complex network of signaling pathways. We hope that by detailing the reported interactions between breast cancer metastasis and natural polyphenols, more attention will be directed to these promising candidates as effective adjunct therapies against metastatic breast cancer in the clinic.

Cyclooxygenase-2 in tumor-associated macrophages promotes metastatic potential of breast cancer cells through Akt pathway

Tumor-associated macrophages (TAMs) promote cancer development and progression by releasing various cytokines and chemokines. Previously, we have found that the number of COX-2+ TAMs was associated with lymph node metastasis in breast cancer. However, the mechanism remains enigmatic. In this study, we show that COX-2 in breast TAMs enhances the metastatic potential of breast cancer cells. COX-2 in TAMs induces MMP-9 expression and promotes epithelial-mesenchymal transition (EMT) in breast cancer cells. In addition, COX-2/PGE2 induces IL-6 release in macrophages. Furthermore, we find that the activation of Akt pathway in cancer cells is crucial for the pro-metastatic effect of COX-2+ TAMs by regulating MMP-9 and EMT. These findings indicate that TAMs facilitate breast cancer cell metastasis through COX-2-mediated intercellular communication.

Membrane progesterone receptors in reproduction and cancer

Progesterone is a sexual steroid hormone that has a critical role in reproductive processes in males and females of several species, including humans. Furthermore, progesterone has been associated with pathological diseases such as breast, gynecological and brain cancer, regulating cell proliferation, apoptosis, and metastasis. In the past, progesterone actions were thought to be only mediated by its intracellular receptor (PR). However, recent evidence has demonstrated that membrane progesterone receptors (mPRs) mediate most of the non-classical progesterone actions. The role of the different mPRs subtypes in progesterone effects in reproduction and cancer is an emerging and exciting research area. Here we review studies to date regarding mPRs role in reproduction and cancer and discuss their functions and clinical relevance, suggesting mPRs as putative pharmacological targets and disease markers in cancer and diseases associated with reproduction.